


Strange Mechanics

by clottedcreamfudge



Series: A Fine Institution [2]
Category: Shadowhunters (TV)
Genre: Bonding, Deflect Rune (Shadowhunter Chronicles), Falling In Love, I make fun of witchlights, In a manner of speaking, Izzy is invasive, M/M, Magic, Magical Buildings, New York Shadowhunter Institute, Sexual Content, Sharing a Bed, Shower Sex, Stamina Rune (Shadowhunter Chronicles), Telepathy, The Institute - Freeform, but in a loving way, magical buildings and their caretakers
Language: English
Status: Completed
Published: 2021-01-26
Updated: 2021-01-26
Packaged: 2021-03-18 22:21:22
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,131
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28999686
Author URL: https://archiveofourown.org/users/clottedcreamfudge/pseuds/clottedcreamfudge
Summary: “Magnus!” Isabelle says when she sees him, Underhill depositing him opposite Alec and stepping into a space nearby. “Thank the Angel you’re here - we think there might have been a security breach at the Institute, but there’s something weird about it.”“Because magical security breaches are so unusual for us,” Jace mutters with a sardonic look at Izzy. “We need one of those boards. ‘It has been zero days since the last magical attack against our defences’.” Magnus tries not to laugh, mostly because he doesn’t ever want to validate Jace, but also because Izzy’s stilettos look very sharp.Alec takes over with a sigh, arms folded across his chest.“Apparently there was an interesting fluctuation in the Angelic power core yesterday,” he says slowly, looking Magnus in the eyes like he’s trying to communicate with him telepathically. “It happened just after I finished my last briefing for the day and lasted about fifteen minutes. In that time, the wards were uncompromised, but several non-essential systems were out of action.”Magnus understands now why Alec had looked so guilty.
Relationships: Magnus Bane/Alec Lightwood
Series: A Fine Institution [2]
Series URL: https://archiveofourown.org/series/2127447
Comments: 86
Kudos: 469





	Strange Mechanics

_“Izzy’s calling an emergency meeting.”_

Magnus’s brain feels like it’s encased in warm tar, and he fights instinctively against the sounds and sensations trying to drag him from the treacly depths of sleep. His back is to Alec, who just said some words that don’t make sense yet, and the feeling of breath tickling the back of his neck is doing some interesting things to his early morning libido. Or early afternoon libido. The curtains are shut, so it’s difficult to tell exactly which of his time-based libidos he should be blaming for the way he pushes back slightly with his hips, immediately finding heat and something _else_ ; something with which he would like to gain intimate familiarity.

“Magnus, I have to get up,” Alec says, sounding a little hoarse and not particularly jazzed about the whole concept. Magnus can relate.

“I’m not stopping you,” Magnus says drowsily, humming delightedly at the large, warm hand that lands on the skin of his hip when he pushes back again; they’re both fully clothed, but the silk of his tunic seems to have slipped up a little in the night. The sharp intake of breath and the press of lips against the nape of Magnus’s neck tells him this fact is appreciated.

“You kind of _are_ ,” Alec murmurs into his neck, and then he’s huffing and the heat and his hand are _gone_ from Magnus’s body. The noise Magnus makes at the loss is undeniably petulant, but he’s going to make an allowance in this case because he’s tired and Alexander is incredibly attractive. And moving away from him.

And _stripping_. 

Magnus sits up and blinks, suddenly more awake than he’s ever been in his life. Alec is down to his underwear now in the dim light of the room, and Magnus realises two very important things simultaneously.

One: Alexander’s body is even better than he remembers.

He saw a little of it yesterday - got his hands on a very _sizable_ part of it, even - and several of his late-night fantasies revolve around what _could_ have happened after he found Alec shirtless and whaling on a punch bag that one glorious time in the Institute’s training room. So yes, he has some practical experience with the body in front of him at the moment. 

But now he can really _look_ , there’s a lot of material to work with. Long, lean legs with strong thighs and calves, broad shoulders, an ass he wants to write sonnets about… And the unmistakable sign of Alec being more than a little affected by having Magnus pressed against him in bed this morning. 

Which leads him to number two: Alec is incredibly unselfconscious about his body. It doesn’t even seem to have occurred to him _not_ to change in front of Magnus, even though this is a very different scenario from whatever weird communal showering/homoerotic locker room nudity Alec grew up with. They had sex on the floor of a sentient elevator yesterday; Magnus is sort of hoping that’s a new one for both of them.

Although, Magnus supposes as he watches Alec pull on a clean t-shirt, it’s very possible that he himself is not the first person to look at Alexander’s body like this, even if Alec has never been aware of anyone else’s gaze before. The thought really shouldn’t make Magnus jealous. None of those people have had Alexander whining plaintively into their neck as he orgasms.

Anyway, the point is that Alec, rubbing sleep from his eyes with the heel of one hand and going for the waistband of his boxers with the other, has not a care in the world for the hammering of Magnus’s heart.

He’s over 400 years old, has slept with enough people (and people-adjacent beings) that his little black book would have to be serialised, and he’s _slamming his eyes closed_ so that he doesn’t faint at the sight of Alec’s semi-hard dick. Which he has already touched. Liberally.

“Magnus, are you okay?” Alec asks, sounding a little more awake and concerned than he had done a moment ago.

“Just pondering the ethics of magically trapping you in here for the next 24 hours,” he says with a sigh, eyes still closed. There’s a pause, some fabric-y noises that _hopefully_ herald the covering up of Alec’s too-distracting body, and then a gentle touch to Magnus’s cheek. He opens his eyes and Alec is blinking down at him, fully clothed and looking adorably confused.

“I slept for 15 hours, which is longer than the Warlock ordered,” he says with a small smile, like he has no idea that bedrooms can be used for other activities. Like he doesn’t recall that Magnus was trying very hard just a few short minutes ago to get _started_ on those activities.

“Yes,” Magnus says drily, sliding his hand over Alec’s where it’s pressed to his cheek, “because that’s the only _possible_ reason I could have for wanting to lock you in here with me. _Sleep_.” Alec’s blush is visible even in the semi-darkness.

“Keep your voice down,” he mumbles, turning his wrist so that his fingers slide between Magnus’s, knuckles brushing his jaw. “She doesn’t need you… Y’know. Giving her ideas.” Magnus realises abruptly that Alec is talking about the Institute. With whom he shares a completely inexplicable magical connection. The room brightens suddenly and Alec winces.

“Good morning to you too,” he says, a little louder, and Magnus startles when he realises the curtains have opened of their own accord, allowing fragmented, stained-glass light to filter into the room unhindered.

“Please don’t take this as a judgment on your sanity, darling, but the fact that you haven’t been pulled in for a psych evaluation by now is a little startling.” Alec rolls his eyes as he stands up, and Magnus feels the loss of their intertwined fingers as keenly as he had the loss of body heat earlier.

“Yeah, because the Clave has always cared _so much_ about my mental wellbeing before now,” he says flatly. Magnus knows the ire isn’t aimed at him, but it pulls at something inside him anyway and he finds himself sitting up just to minimise the distance between them.

“I didn’t mean-” he begins, soft and placating, but Alec cuts him off with a weary sigh and a raised hand.

“I know, I’m… Look, it’s fine.” At Magnus’s raised eyebrow, Alexander huffs out a self-deprecating laugh. “Right, obviously it’s not _fine_ , but-”

“Alexander, all I meant is that, while _you_ are incredible, your Shadowhunters are just incredibly unobservant.”

“I dunno, I think everyone here managed to figure out _some_ stuff about me without much difficulty,” Alec says, sounding a little pissy - and hell if that doesn’t do something for Magnus right now. It’s totally inappropriate, but he’s always had this really peculiar reaction to Alec frowning and gritting his teeth. Given that Magnus now _knows_ that this pent-up frustration can be channelled into something truly spectacular, it’s probably only going to get worse.

“And yet you’re the only one here that the Institute cares to talk to,” Magnus says with a smile, pushing down the urge to pull this ridiculous, tightly-wound man back into bed. “I’d say that means something.” Alec relaxes a little around the shoulders and rolls his neck.

“Yeah, well,” he says, sounding suspiciously _airy_ now, “maybe I just appeal to _really old things._ ” Magnus narrows his eyes.

“Less and less by the second, darling.” The lopsided grin Alec sends his way makes Magnus ache and he clears his throat past the nonsensical lump trying to form there. “Anyway, I’d better get back before someone sees me and makes an assumption about my virtue.” Alec raises his eyebrows. “Well, alright, _your_ virtue then,” Magnus amends. He left his own somewhere in the 18th century. 

“Okay, but-” Alec’s phone, abandoned on the bed, begins to buzz enthusiastically. Snagging it from the rumpled bedsheets, he rolls his eyes and answers it tersely.

“I’m on my way, Iz, I swear.” Magnus hears the tinny, distant sound of Isabelle Lightwood’s voice, though he can’t hear what she’s saying. Alec’s eyes dart over to Magnus, swallowing almost audibly. “Um, yeah. That’s fine, I’ll get him over here. See you in a minute.” Alec hangs up and shoves the phone into his pocket with a sigh.

“Magical emergency?” Magnus asks with a small smile. 

“Apparently,” Alec says drily, “this meeting warrants the attendance of the High Warlock of Brooklyn. And _apparently_ he’s not answering his phone.” Magnus glances over at his jacket, which is folded carefully over the back of a chair in the corner of Alec’s bedroom. His phone is probably in one of the pockets, being ignored in favour of much nicer things. He vaguely remembers silencing it with a wave of his hand at some point, but he’s not sure if he feels bad about that or not. He hopes nobody died.

“Maybe he had a prior engagement. He’s a busy and important man - not to mention devastatingly handsome.”

“Or _maybe_ he was taking a nap,” Alec counters, and he’s obviously trying to look serious, but he’s answering Magnus’s grin with a helpless smile of his own almost instantly. Magnus really is in quite a lot of trouble. 

“Well, luckily for you, I’ve managed to locate him,” Magnus says with a sweeping gesture at himself - which is when he realises he’s still in yesterday’s clothes. He frowns down at his slightly creased tunic. “And by the looks of it, he’s a dirty stop-out.” Alec makes a choking noise and when Magnus looks at him, he’s staring at the ceiling with concrete determination. Magnus would find the flush creeping down his neck adorable if it weren’t for the sun hitting his deflect rune _just right;_ it makes him think of much less wholesome things.

Magnus takes pity on Alec and creates a quick portal to his loft so he can change and come back. He explains that this way he can portal to the front door instead of back to Alec’s bedroom, making all of this look significantly more above-board than it is. This suggestion, however, leads to a whole new set of problems.

“You're telling me you can usually create portals straight into the Institute.” Alec’s voice is flatter than week old soda. “No, you know what,” he says with a sigh before Magnus can respond, running a hand over his face, “that makes sense. These are your wards. The Institute loves you. I don’t know why I’m surprised by any of this.”

“I was _so sure_ I’d mentioned it,” Magnus lies blithely, before stepping through the portal and closing it behind him.

➸

He arrives back outside the Institute’s front doors fifteen minutes later, and is escorted inside by Underhill, who seems a little harried.

“Glad Alec managed to get hold of you,” he says as he leads Magnus through to the op centre, weaving through various Shadowhunters with practised ease. “It’s been a bit manic since we noticed the potential breach in security, and we’ve exhausted all the usual diagnostic methods.” Magnus tries to look innocently concerned, but innocence is never a look he’s worn with any kind of realism.

“Always happy to be of service,” Magnus replies solemnly, which isn’t precisely a lie. He absolutely wants to be of service, but mostly to Alexander, and almost solely in ways that he doesn’t have a fee menu for.

The table in the op centre is crowded with the usual suspects: Isabelle, looking slightly murderous; Jace, jaw set but eyes unsurprisingly on Clary, who is herself lost in thought; and, of course, Alec, who looks-

 _Incredibly guilty_.

“Magnus!” Isabelle says when she sees him, Underhill depositing him opposite Alec and stepping into a space nearby. “Thank the Angel you’re here - we think there might have been a security breach at the Institute, but there’s something weird about it.”

“Because magical security breaches are so unusual for us,” Jace mutters with a sardonic look at Izzy. “We need one of those boards. ‘It has been zero days since the last magical attack against our defences’.” Magnus tries not to laugh, mostly because he doesn’t ever want to validate Jace, but also because Izzy’s stilettos look very sharp.

Alec takes over with a sigh, arms folded across his chest.

“Apparently there was an _interesting_ fluctuation in the Angelic power core yesterday,” he says slowly, looking Magnus in the eyes like he’s trying to communicate with him telepathically. “It happened just after I finished my last briefing for the day and lasted about fifteen minutes. In that time, the wards were uncompromised, but several non-essential systems were out of action.”

Magnus understands now why Alec had looked so guilty.

“I see,” he says seriously, meeting Alec’s gaze and raising his eyebrows in question. _‘How are we playing this?’_ The response is, surprisingly, verbal.

“So, you wanna field this one?” Alec looks embarrassed and resigned, but there’s steely determination in his eyes - like he’s made a choice and he’s sticking with it. Well, if Magnus is being given _permission_ …

“Certainly, Alexander,” he says smoothly, before addressing the rest of the assembled Shadowhunters. “Well, the good news is that there hasn’t been a breach of your systems.” The ripple of relief that goes around the table is palpable; Magnus vaguely sees Alec dismissing Underhill with a nod. “The _other_ bit of good news,” he continues brightly, “is that the Institute has decided to join in with everyone here in their attempts to meddle in Alexander’s love life.”

This pronouncement is met with silence, before Clary pipes up.

“Is this like with cars?” she asks, eyebrows raised. “A lot of mundanes name their cars and bikes or whatever. They’re nearly always female. Are we gendering the Institute now?”

“I feel like that’s not the part of my explanation that you should be focusing on,” Magnus says, amused. Jace snorts.

“That _really_ wasn’t an explanation.” Magnus concedes this point with a nod, and is about to elaborate when Alec intervenes with a frustrated sigh.

“Alright, practical demonstration,” he says, and before Magnus can say something like _“I don’t think Jace wants to see that”_ , he’s leaning back towards one of the stone pillars and pressing his hand to it. “People are worried,” he murmurs with a roll of his eyes. “Just, I dunno… make the lights flicker. Play some Beethoven or something. Don’t go overboard.” 

The Institute goes one better for her golden boy.

The opening strains of Beethoven’s _Moonlight Sonata_ play softly through the speakers that are usually used for barking orders and issuing warnings; it’s quiet, just enough that the five of them can hear it, but Clary jumps noticeably and even Jace looks mildly alarmed. The lights don’t flicker, but they do dim as the electronic surface of the table starts to flow like water, every fluctuation matching perfectly with the cadence of the music. It’s hypnotic, and Magnus can’t help but think that the Institute would make a truly fabulous Warlock. She has such a well-honed sense of the dramatic.

“Show off,” Alec mutters, but he’s smiling as he takes his hand away from the pillar, falling back into parade rest automatically. The music slowly softens and fades out, the surface of the table settling back into electronic static.

“What the hell did I just see?” Jace asks wonderingly, expression caught between amazement and horror.

“The Institute has favourites, it would seem,” Magnus says with a smile.

“She trapped me in an elevator, Magnus,” Alec counters with an eye roll.

“Yes, but she trapped you in there with _me_ , which is a significantly better deal for everyone involved.”

“You are so-”

“Hold on just a second,” Izzy interrupts, hands gripping the edge of the table as she leans towards Alec, eyes glinting with dangerous delight. “You’re telling me the Institute is _pimping you out?_ ” Alec glares at her.

“You make it sound so unsavoury, my dear,” Magnus says with a put-upon sigh. She turns to him with a frankly _lewd_ grin.

“I really hope it _was_ ,” Izzy says with a cackle, and _unfortunately_ Alec’s refusal to meet her eyes after that is tantamount to a heartfelt confession in her eyes. “By the Angel - Alec! I can’t believe you didn’t tell me _immediately_. I’d have thrown a party.”

“Yes, I can’t imagine why I’d want to avoid that,” Alec says with a grimace. “Also, nothing happened.” He's such a fucking _liar_ , Magnus thinks with admiration. Clary holds her hands up.

“Wait, so - the Institute shut you in an elevator with Magnus for fifteen minutes? Surely that wouldn’t account for the amount of power that was siphoned away from the core.”

“Perhaps not. However, the amount of power required to turn my own magical signature back on me in order to _keep_ me in the elevator was likely quite substantial,” Magnus explains calmly. “If it had just been a case of having to keep Alexander from leaving, I’m not sure you’d even have noticed.”

“Then there was the whole temperature thing,” Alec reminds him, rolling his shoulders slightly; his tongue darts out to wet his lips like he’s _remembering,_ and Magnus is abruptly aware of how many people there are around them.

“Temperature thing?” Jace asks, eyebrows raised. “What _temperature thing_.” 

“The Institute raised the ambient temperature. A bit.” Alec looks like he would rather be literally anywhere but here. Izzy, on the other hand, looks like this is the best day of her life, and also like she’s aware it might be about to get better.

“How much is ‘a bit’?” she asks gleefully, and Alec runs a hand through his hair with a frustrated sigh.

“Like, thirty degrees. Anyway, it doesn’t _matter_ , because there wasn’t a security breach and now I need to go and-” Alec breaks off with a harsh exhalation of breath and closes his eyes. “I need to go and be somewhere else. _Anywhere_ else.”

“We aren’t done-”

“We really are,” Alec interrupts, glaring at Izzy like that look has ever worked on her before. “And also, we’re never speaking of this again.”

“Hold on, is this why the coffee you get from the first-floor machine always tastes better than mine?” Jace asks suddenly, looking severely put out at the idea that the Institute might love Alec more than it loves him.

“Yes,” Alec says bluntly. “You get ichor everywhere. And you don’t put the books back right in the library.”

“The system doesn’t make any sense-”

“I’m _aware_ ,” Alec says through gritted teeth. “But she likes it colour coded, and the Dewey Decimal system never sticks. How hard is it to put a book back where you found it, Jace?” This is a distinct turnaround from his threats in the elevator yesterday.

“Most of the books are brown, Alec,” Jace growls. “I don’t know the fucking difference between beige and _field mushroom_ or whatever.”

“I feel like this meeting has run its course,” Magnus says quickly, before this argument can get out of hand; Alexander is apparently weirdly passionate about the library. Magnus is still trying to figure out why he finds it so attractive, besides the simple fact that he finds almost everything about Alec attractive.

“Oh, come on, we deserve details,” Isabelle says excitedly, slapping her hands down on the table and making Clary jump again.

“We got stuck in an elevator and it was too warm,” Alec says blandly; Magnus tries very hard not to smile. “End of story.”

“But-”

“Oh look,” Magnus says with no small measure of relief, pointing at where Underhill is marching towards them, a bunch of bedraggled, ichor-soaked Shadowhunters hot on his tail. “A convenient distraction seems to be on its way.”

Alec has never looked so happy to be told about a nest of Shax demons.

➸

Magnus helps dispatch the demons, since he’s in the area anyway, which means it’s only polite of him to offer his services with clean-up.

“This is _not_ clean-up,” Alec says against his mouth as Magnus pushes him into the shower at his loft, still fully clothed and splattered with ichor and blood. Both of these things are objectively disgusting. It shouldn’t be hot. Why is it _hot?_

“I beg to differ,” Magnus says firmly, following him under the warm spray and sealing their mouths back together. Alec is delightfully responsive, hands clutching at Magnus's shoulders as he allows himself to be devoured; there's a desperation to the pressure of his mouth, to the little noises that rise unbidden from his throat, and Magnus is _weak_ for it.

"I've wanted this _all day_ ," Alec pants, and _fuck_ Magnus loves how being horny seems to make Alec incapable of anything but desperate, gasping honesty. Alec pulls away to drag his sodden shirt over his head, casting it aside without a second glance. It lands on the bathroom floor with a wet thud, and Magnus's previously pristine button-up follows shortly after. “Wanted you since-” Alec sucks in a sharp breath when Magnus licks up his neck, tongue following the path of water droplets clinging to the dark zigzag of his deflect rune. “Since waking up with you in my bed.”

"Your mattress is appalling,” Magnus confides with a hum, before biting down right in the middle of the rune - to truly _spectacular_ effect. Alec makes a noise that sounds as though it’s been punched out of him, hips snapping forward as his fingers dig bruises into Magnus’s biceps.

“Fuck, okay,” Alec says in a strained voice that makes Magnus actually _giddy_ with want. “That’s a thing.” _It sure is_ , Magnus thinks somewhat hysterically, fumbling with Alec’s belt buckle for the second time in 24 hours. Why is Alec wearing clothes again? What a horrible and unnecessary thing to be doing.

“Why are you dressed?” he asks nonsensically, and Alec makes a noise of protest that’s quickly swallowed up by Magnus’s mouth on his. They kiss frantically, peeling off layers of wet denim and cotton until there’s nothing left but skin; Alec pulls away with a deep, shuddering breath, pushing sopping wet hair out of his eyes.

“You dragged me in here,” he argues, not sounding even a little bit mad about it.

“I meant _ever_ ,” Magnus clarifies, pushing Alec back into the tiles more firmly. “Why are you dressed _ever?_ ”

“I have a job,” Alec says with a strangled laugh, running his hands up and down Magnus’s back before pulling him in by the hips. Magnus feels fire lick up his spine at the contact, and he pulls Alec back down into a messy kiss, interrupting his argument that _“people would probably be weirded out”;_ as if pretty much everyone’s day wouldn’t be improved by Alec forgetting how clothes worked.

“I’m going to blow you now,” Magnus says matter-of-factly when he pulls away, breathing hard and staring into Alec’s eyes with an intensity that probably isn’t warranted. Alec’s lips are parted, mouth delightfully red and almost bruised by the ferocity with which he’s been kissed today. His pupils are huge, and the fact that he’s soaking wet and flushed from his cheekbones down to his chest is just… a really nice bonus. Magnus wants to take photographs for posterity.

“Um,” Alec eventually manages, breath coming in fits and starts as he attempts, presumably, to remember how to speak. “I - are you-?” He closes his eyes with a frustrated huff of breath then opens them and tries again. “Am I meant to argue with you? Because I don’t think I want to.”

“I am incredibly persuasive,” Magnus allows, before sliding to his knees and taking Alexander into his mouth.

Alec may not technically be a virgin anymore - and don’t get Magnus started on _that_ concept, because he’ll argue about it for days, provided his mouth isn’t otherwise occupied - but Magnus knows first-hand how intense a good blowjob can be. He is providing a _very_ good blowjob right now, and not just because Alec doesn’t have anything to compare it to; Magnus is just… good at this. He enjoys it. He has practised _a_ _lot_. He’s going to use every bit of his not inconsiderable skill to make this _incomparably_ good for the ninety seconds Alec’s probably going to last for.

Except that, an impressive five minutes into this incomparably good blowjob, Alec tugs at his hair in a way that, rather than suggesting ‘I’m about to come’ actually gets across ‘hey, can we talk for a second?’ The unintentional thrusting of his hips, as well as the muffled curses and nonsensical praise Alec’s been murmuring since the second Magnus got Alec’s dick in his mouth, are at odds with the vaguely apologetic look on his face when Magnus looks up.

“Magnus, I’m so sorry, I-” Alec takes a deep breath, and his fingers clench a little where they’re still buried in Magnus’s hair. “I, um, used my stamina rune. When we fought those demons? It’s not worn off yet. This might-” He swallows and licks his lips. “It might take a while.” He looks so forlorn and _sorry_ , like he hasn’t just delivered some incredibly sexy and exciting news. News that opens up a whole world of delicious possibilities, many of them borderline impossible to achieve without angelic interference.

Magnus stands to kiss Alec like his life depends on it; it’s quite possible that it does, given how addicted he’s become to the taste of Alexander’s mouth already. 

“I have never loved Shadowhunters more than I do right now,” Magnus says frankly, voice low and a little rough with desire.

“All Shadowhunters?” Alec says with a grin as Magnus grabs a shampoo bottle at random and starts to lather the stuff into Alec’s dark, sodden mop of hair.

“I have a favourite,” he admits, and Alec’s eyes slide closed under the press of Magnus’s fingers against his scalp. “He’s naked in my shower right now, and I shortly hope to have him naked in my bed. He seems amenable.” Alec tilts his head obediently so that Magnus can rinse the shampoo from his hair.

“Sounds promising,” Alec says with a smile, swaying into Magnus’s space, eyes still closed. He’s unfairly gorgeous like this, especially given that they just spent a ridiculous amount of time clearing out a huge and angry nest of Shax demons. In actual fact, the adrenaline had just made Alexander burn brighter and more fiercely; Magnus had wanted him from the second he’d shot that first arrow, but now he thinks he might need him.

“Doesn’t it _just?_ ”

➸

“That’s some rune,” Magnus gasps, clutching at Alec’s neck and ass with blunt fingernails, hoping faintly that they’re leaving marks. When he inevitably dies from being fucked excruciatingly well by someone who probably even feels guilty about _masturbating_ , he’d like to leave Alec something to remember him by.

“Thanks,” Alec grinds out past gritted teeth, all his concentration apparently on fucking Magnus into next week. “I drew it myself.” Magnus gives a helpless little hiccupping laugh, and the noise Alec makes in response is almost wounded. “Don’t _laugh,_ ” he hisses desperately, his hips coming almost to a complete stop at the tightening of Magnus around him.

“Stop being _hilariously charming_ then,” Magnus counters breathlessly, before grinding back against Alec’s cock in a move that has the other man collapsing onto his forearms on a sharp intake of breath.

“ _You’re_ charming,” Alec says stupidly, a little muffled where he’s mouthing at Magnus’s neck; the re-started rhythm of his hips gets a little more purposeful, and any pithy response Magnus might usually be able to conjure up suddenly seems very far out of his reach.

Alec had been so careful opening him up, like Magnus was something soft and breakable, rather than a seasoned pro with an alarming number of conquests under his belt. Even when he’d tried to hurry things along a little, Alec had stayed steady, until Magnus was pushing back against three of those long fingers and begging for more. Somehow, his 400-odd years on the earth still hadn’t prepared him for Alexander Lightwood and his tender insistence on being _good_ at _everything._

Now, Alec is sharper, less coordinated; he’s clearly aware that he’s on borrowed, angelic time, and that the only thing keeping him from having a traditionally virginal experience right now is the Shadowhunter equivalent of a temporary tattoo.

Magnus likes the contradictions in Alec as much as anything else. He’d been soft and pliant under Magnus’s hands in the shower; focused and dedicated as he’d made Magnus ready for him; hungry and a little out of control as he’d settled inside, gasping and saying things that didn’t make sense but felt very important nonetheless.

Magnus is close - has probably been on the edge for longer than he’d care to admit. The coiled power and tension in Alec’s body is unbelievably hot, and having all of that on top of him and _inside_ him is almost too much to bear. It’s like being up close and personal with a supernova.

“ _Please_ tell me you’re almost there,” Alec groans into his neck, teeth grazing the skin there almost as an afterthought. Magnus hisses and hooks one leg around Alec’s thighs, trying to get him impossibly deeper.

“ _Yes_ ,” Magnus manages on an outward breath, because Alec’s probably completely unaware of this but he’s been brushing unerringly up against Magnus’s prostate for the last five minutes and he’s just about ready to come undone. Maybe there’s a rune for ‘really good in bed’, he thinks hysterically as Alec seals his mouth around Magnus’s Adam’s apple and _sucks_. The sharp pressure makes Magnus gasp and, in a move that surprises him as much as anyone else in this equation, comes immediately between them.

“Oh _fuck_ ,” Alec says succinctly, thrusts shallow and uncoordinated as he very quickly follows suit, face pressed firmly into Magnus’s neck as he comes with a broken sob. Magnus clings to him because he’s not sure what else to do; it all feels like too much and not enough, and he’s still shaking a little with the aftershocks when Alec finally pulls back far enough to kiss him. It’s a mess, and Magnus feels it like electricity in his bones, hot and familiar for all that it’s so terribly, achingly new.

“I’ve had my problems with Raziel’s children in the past,” Magnus says with a sigh when Alec settles next to him, their legs tangled together like badly knotted pretzels, “but I’m a convert. Sign me up for whatever the hell _that_ was.”

“I’m not an expert,” Alec says in a voice that’s still low and a little gravelly, “but I think that was sex.”

“You can say that again,” Magnus says dreamily, turning onto his side so he can pull Alec into a long, very thorough kiss. He vaguely thinks about cleaning up a bit, but the hot, slow slide of Alexander’s mouth against his own pushes everything else into the background until he can’t focus on anything but the points where their bodies meet.

“Are you, um,” Alec murmurs eventually, swallowing as Magnus starts pressing lazy, open-mouthed kisses down his throat. The hickey over his deflect rune is blooming _beautifully_ , Magnus is pleased to see. “Are you uncomfortable?” How Alec manages to be adorable even when he’s trying to ask Magnus about his _ass_ is unfathomable.

“Personally, I quite like being able to feel you,” Magnus says airily, entirely unsurprised but gratified nonetheless when he feels the hitch in Alec’s breathing. He carefully takes one of Alec’s hands in his and moves it round to where he’s still open and wet, gasping quietly when Alec obediently slides two fingers back inside. “Yes, angel,” he breathes, and the answering whimper from Alec before Magnus is kissed breathless is _incredibly_ promising.

➸

Before now, Magnus has seen Isabelle Lightwood smug. She has a lot to be smug _about_ , in general, from being able to outrun Olympic athletes in 6-inch heels, to somehow never having lipstick on her teeth. However, her reasons for being smug right now have nothing to do with her own achievements, and everything to do with Alec completely forgetting to use an _iratze_.

“Did you get mauled by a _bear_?” she asks delightedly, fingers immediately going to prod at the bruises on Alec’s neck. He grabs her wrist before she can get there, glowering and shoving her hand back at her.

“Izzy,” he says warningly, and Magnus is a little ashamed to say that the tone of voice gives him a thrill. Isabelle turns on _him_ now with an almost feral grin.

“Magnus, why does my brother look like an extra in a mundane vampire movie?”

“I graciously allowed him the use of my bathroom following our battle with those Shax demons,” Magnus says smoothly, trying not to smile. “I believe he had a run-in with a neck-high towel rail.” The lie goes over about as well with Alexander as it does with Isabelle.

“Please stop trying to help,” Alec says flatly, face delightfully pink as he leans against a wall for strength. Isabelle cackles and a second later a small piece of stone falls from the ceiling and ricochets off her head, skittering down the hallway to land innocently a few feet away. Izzy winces and glares up at the ceiling; Alec now looks as though he’s trying not to laugh.

“This is _favouritism_ ,” Izzy complains, and Alec shrugs, patting the wall fondly before standing upright again.

“Get someone in maintenance to have a look at that ceiling, would you, Iz?” he says, and he’s grinning now, Magnus’s heart beating double time at the sight of it. “Wouldn’t want that happening to someone undeserving.” Izzy punches him in the arm with a scowl, but her face is visibly softening even as she turns on her heel and marches away.

“That could’ve gone a lot worse,” Magnus says brightly.

“It would’ve gone better if you’d done your _thing_ before we came back here,” Alec mutters, waving a hand as if to indicate _magic_ before folding his arms.

“Do _iratzes_ not work on sex bruises?” Magnus asks mildly, and is gratified to see the flush creeping back up Alec’s neck. He pushes his advantage, stepping a little closer into Alec’s space; there’s still enough room there that they don’t look _suspicious,_ but Magnus is close enough to see the dilation of Alec’s pupils and the way his eyes dart immediately to Magnus’s mouth. “Perhaps it’s selfish of me, but I rather enjoy being able to see the evidence of having had my mouth on you.” Alec closes his eyes on a shaky breath.

“We can’t do this here,” he says, sounding turned on and apologetic, which is when every light in the building decides to go out.

“Should we be panicking?” Magnus asks as witchlights begin to light up the op centre up ahead. It’s strange, he thinks; it’s not really that dark, what with the monitors still on and the fading light from outside. Also, all of those Shadowhunters have phones with actual torches on, so they’re just using their weird glowy stones to be _dramatic;_ Magnus wouldn’t know anything about that. 

Alec groans and raises his eyes to the ceiling. “Panic? No. I’m choosing to feel deep, deep embarrassment.” The elevator doors open to Magnus’s right and he and Alec turn in synchronised slow motion to stare at it. The lights are most definitely on in _there_.

“Does she think we don’t know how to have sex anywhere else?” Magnus muses, and Alec makes a noise like a wounded animal and slumps back against the stones with his eyes closed.

“Alright, that’s enough,” he says quietly, voice a little strained, both hands flat against the wall. “I love you but we’re… you know. _Together_. You did it. Well done. This really isn’t necessary.” He hesitates as the hallway stays resolutely dim, then sighs. When he continues, his voice is firm. “I’m happier, I promise.” The lights come up so fast Magnus winces, and he swears he sees a few excitable sparks coming off some of the bulbs. Alec sags a little against the wall with relief, before straightening up and shooting a look at Magnus. “I’m gonna have to go and smooth this over. Just… stay here.”

“I’ll be right here,” he says with a soft smile, Alec’s lopsided grin returning and knocking Magnus on his ass just a little. He turns towards the op centre, looking equal parts determined and resigned, and Magnus thinks he might be done for when he realises that even _that look_ has his heart stuttering in his chest. “Oh, and - Alexander?” Alec stops and turns back to him with a raised eyebrow. “I like the sound of ‘ _together’_.”

Alec’s smile puts witchlight to _shame_.

“Yeah,” he says softly. “I like it too.”

**Author's Note:**

> Apparently this needed a companion piece... So I wrote one. Maybe one day I'll be able to stop, but that day is not today.
> 
> Anyway, hope you enjoy my second rush job this week, which includes the shameless abuse of Alec's stamina rune, as well as Magnus doing to his deflect rune what I wish I could do to it. Just a bit. If I weren't married. And Alec weren't gay and fictional.


End file.
